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United States Patent |
5,506,294
|
Westerhoff
|
April 9, 1996
|
Non-volatile material
Abstract
A non-volatile compound useful as a solvent and a method of manufacturing
the compound. The compound is formed from heating a combination of a
lactide and a drying oil which has conjugated double bonds. The compound
is particularly useful as a resin solvent for use with coatings, paints
and printing inks. In addition, it can be used as a compatibilizing agent.
Inventors:
|
Westerhoff; David (P.O. Box 1192 Goose Creek La., Middleburg, VA 22117)
|
Appl. No.:
|
393913 |
Filed:
|
February 24, 1995 |
Current U.S. Class: |
524/500; 427/384; 528/357; 549/274; 554/24; 554/30; 554/31 |
Intern'l Class: |
C08J 003/00; C08G 063/78; C07D 309/32; C07B 041/12 |
Field of Search: |
554/24,30,31
549/231,274,415,448
528/357
524/500
|
References Cited
U.S. Patent Documents
2033131 | Mar., 1936 | Ellis | 106/252.
|
2188882 | Jan., 1940 | Clocker | 549/253.
|
2623056 | Dec., 1952 | Elwell | 554/30.
|
3830763 | Aug., 1974 | Gillan et al. | 554/30.
|
5374743 | Dec., 1994 | Thayer et al. | 549/274.
|
Foreign Patent Documents |
467226 | Aug., 1950 | CA.
| |
Primary Examiner: Yoon; Tae
Attorney, Agent or Firm: Whitham, Curtis, Whitham, & McGinn
Parent Case Text
CROSS-REFERENCE TO RELATED APPLICATIONS
This patent application is a continuation-in-part patent application of the
U.S. Patent Application having U.S. Ser. No. 08/162,454 filed on Dec. 3,
1993, now U.S. Pat. No. 5,405,935, and the complete contents of that
patent application are herein incorporated by reference.
Claims
I claim:
1. A non-volatile material formed by the reaction of a cyclic keto enol
tautomer with an oil having at least one conjugated double bond.
2. The non-volatile material of claim 1 wherein said product is formed by
reacting 5-25% by weight of said cyclic keto enol tautomer with 75-95% by
weight of said oil.
3. A method of producing a non-volatile material, comprising the steps of:
combining a cyclic keto enol tautomer formed from a compound having a two
or more carboxylic acid moieties or at least one hydroxy moiety and one
carbocylic acid moieties with an oil; and
heating said combination of said cyclic keto enol tautomer and said oil to
produce a non-volatile material.
4. A method of using the non-volatile material of claim 1 comprising the
step of applying the non-volatile material to a substrate as a varnish.
5. A method of using the non-volatile material of claim 1 comprising the
step of incorporating said non-volatile material into a mixture of two or
more polymeric compounds as a compatibilizing agent.
Description
DESCRIPTION
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention generally relates to a compound which can be used as
a solvent and a method of manufacturing the compound. More particularly,
it is directed to a compound which is formed from heating a combination of
a lactide and a drying oil which has conjugated double bonds. This
compound is non-volatile and is particularly useful as a resin solvent for
use with coatings, paints and printing inks. It can also be used as a
compatibilizing agent for resins.
2. Description of the Prior Art
The formulations of most oil based coatings, paints and printing inks
include a solid resin which is dissolved in a solvent. These compounds
often contain other ingredients depending on the intended use and desired
characteristics. It is common to add pigments or dyes to obtain colored
coatings. It is also known to include additives to determine the
characteristics of the coating. Some examples of features which can be
adjusted include: the gloss level, the mildew resistance, and the adhesive
properties.
Solvents are usually organic compounds and are used to alter the physical
properties of a compound. The solvents currently in use are generally
volatile, causing them to be evaporated into the ambient air. The volatile
organic compounds are a major cause of air pollution and therefore, they
are subject to a variety of local, state and federal regulations. These
regulations and the potential for stricter regulations in the future have
prompted the manufacturers of these products to investigate alternatives
to these solvents. Although a variety of alternatives have been developed,
the majority possess draw backs which have prevented their adoption for
general commercial use. The draw backs of the alternatives include poor
solvency, high toxicity, short shelf life and the production of toxic
by-products.
SUMMARY OF THE INVENTION
It is therefore an object of the present invention to provide a compound
which can be used as a solvent and which is nonvolatile.
It is another object of the present invention to provide a process for the
manufacture of a compound which can be used as a solvent and which is
non-volatile.
It is another object of this invention to provide a non-volatile solvent
which can be used in both water based inks such as gravure printing ink
and in organic inks such as lithographic ink.
It is yet another object of this invention to provide a compound which is
non-volatile which is useful as a varnish on furniture and other wood
products.
It is also an object of the present invention to provide a solvent which
can dissolve a broad range of resins and is able to form a film.
It is a further object of this invention to provide a compound which is of
low toxicity.
It is another object of this invention to provide a solvent for use in
coatings, paints and printing inks which can replace organic compounds.
According to the invention, there is provided a method for manufacturing a
compound wherein an alpha hydroxy acid, lactic or glycolic acid is heated
to remove all of the water. The heating produces a cyclic keto enol
tautomer. For example, in the case of lactic acid, a lactide is produced
as the cyclic keto enol tautomer. In the case of lactic acid, a lactide.
The lactide is combined with any drying oil which includes conjugated
double bonds and the mixture is heated. The resulting product is useful as
a solvent and has successfully been combined with a number of resins and
other produces.
DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT OF TIE INVENTION
The process of the present invention produces a compound which is useful as
a solvent, for coatings, paints and inks and as a compatibilizing agent.
The first step in the production process is to heat a hydroxy carboxylic
acid or dicarboxylic acid to a temperature at which all the mechanical
water and one mole of chemical water per mole of acid is removed. In the
preferred embodiment the acid is lactic add, glycolic acid or alpha
hydroxy acid. It is most preferred to use lactic acid. The minimum
temperature at which the desired amount of water is removed is
approximately 150.degree. C. However, it should be understood that heating
temperature and heating conditions (e.g., pressure, volume of hydroxy
carboxylic acid, etc.) can be varied within the practice of this
invention. The removal of the water from the acid results in the formation
of a cyclic keto enol tautomer. If lactic acid is the starting compound,
the produce is a lactide which can be represented by one of the following
structures:
##STR1##
If desired, derivatives of the cyclic keto enol tautomer can be formed by
esterification reactions at the site of the hydroxy constituents or by
other means. For example, substituted (e.g., halogenated, etc.) and
unsubstituted C.sub.1-30 moieties can be added via esterification to form
a suitable derivative. The cyclic keto enol tautomer is then combined with
a drying oil which has conjugated double bonds.
It is preferred to use approximately 18% by weight of lactide and
approximately 82% by weight of a drying oil or a combination of drying
oils. However, the amount of lactide or cyclic keto enol tautomer can
range from approximately 5% to 25%. The preferred drying oils include
linseed oil, tung oil, oiticica oil, soya oil, dehydrated castor oil,
other dehydrated vegetable based oils or other commonly known oils. It
should be understood that a wide variety of oils having, for example, 5-50
or more carbons with one or more conjugated double bonds may be useful in
the practice of this invention.
The combination of the cyclic keto enol tautomer and drying oil is heated
to form the non-volatile solvent. It has been found that optimum results
can be achieved by heating at temperatures of approximately 220.degree. C.
for a period of approximately two hours. It is anticipated that different
heating schedules could also be employed (e.g., longer times at lower
temperatures and shorter times at higher temperatures). The resultant
product is characterized as being a liquid which ranges in color from
clear amber to straw. The viscosity of the product was measured in a
number two zahn cup and was found to be 19 to 26 seconds.
It has been determined that having small quantities of chromium, iron, or
other transition metals, and particularly those having a valence of 3,
aids in the formation of the product. Specifically, a superior reaction
product is obtained when the cyclic keto enol tautomer and drying oil are
combined with less than 100 ppm of a transition metal during heating.
Optimal results were obtained when approximately 8-10 ppm of chromium was
present or when 6 ppm of iron and 3 ppm of chromium was present. Other
combinations of transition metals having low concentrations (e.g., less
than 10-20 ppm) may have similar advantages. It has been found that
sufficient chromium content for forming the reaction product can be
contributed simply by using a stainless steel vessel when heating the
cyclic keto enol tautomer and drying oil. By contrast, when a glass
reaction vessel was employed, precipitation of solids occurred. A glass
reaction vessel might be suitable if a sufficient quantity of chromium
salt or other metal complex is added to the reaction mixture.
As an alternative to the two step process of first forming a cyclic keto
enol tautomer and then combining the cyclic keto enol tautomer with a
drying oil, the reaction product may be formed in a single seep by heating
a mixture of a drying oil and a hydroxy carboxylic acid or dicarboxylic
acid that is capable of forming a cyclic keto enol tautomer.
This product is useful as a solvent and can be used with resins and
printing inks. In addition, it can also be used to compatibilize
polypropylene and polystyrene resins which are used in injection molders
and extruders. The product also can be used as a varnish on furniture and
wood products.
The product of the above described process can be used to dissolve resins.
In particular, it has been shown to successfully form solutions with
hydrocarbons, phenolics, acrylics, styrene acrylic copolymers and alkyd
resins. These compounds were preferably approximately 40% by weight of the
solution. The solutions which were formed were clear and were able to form
hard durable films which ranged in thickness from 0.5 to 2 mils.
The product can also be used in the manufacture of lithographic printing
inks. Table I provides examples of combinations which can be used to
produce printing inks.
______________________________________
Overprint
Sheetfed No
varnish web heat
______________________________________
Solvent replacement (product)
65% 28% 37%
Bodied tung oil -- 25% 20%
Styrene acrylic copolymer
31% -- --
Carbon black linseed flush
-- 45% 40%
Micro crystalline wax
-- 2% 1%
Acrylic resin 4% -- --
Talc -- -- 2%
______________________________________
The printing inks manufactured using the product, produced as described
supra, were found to create a durable hard film and excellent print
quality. The drying time of the inks was between nine and fifteen minutes.
The product has been found to be useful in both water based printing inks
such as gravure printing ink and in organic inks such as lithographic
inks. For example, gravure printing ink formulations including 0.1-5% of
the product of this invention and 95-99.9% gravure printing ink. Water
based gravure printing inks exhibit an uneven rough visual appearance. The
roughness is caused by uneven absorption of ink into the substrate. This
has been referred to as galvanizing in the gravure printing industry. The
addition of 1 to 5% of the reaction product to a water based alkaline
gravure ink eliminates this phenomena and produces a printed result that
has a uniform even appearance.
The material can also be incorporated into other water based coatings. The
material is water miscible with the addition of an alkaline material until
a pH greater than 7.0 is achieved. Ammonium hydroxide is the preferred
material for coating applications.
The product of the present invention is also useful as a compatibilizing
agent. A mixture of approximately fifty (50) parts of polypropylene, fifty
(50) parts of polystyrene and one (1) part of the product was adsorbed on
four (4) parts of ethylene propylene styrene terpolymer. The resultant
material was extruded to produce a band which as approximately 1.5
millimeters by 12 millimeters. The extruded material was of a uniform
consistency and could be bent without breaking. For comparison purposes,
the mixture was also prepared without the product and was extruded. This
material was not compatibilized and fractured when deformed.
While the invention has been described in terms of the preferred
embodiments, those skilled in the art will recognize that the invention
can be practiced with modification within the spirit and scope of the
appended claims.
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